1. Field of the invention:
The present invention relates to an electrode type steam vaporizer. More particularly, it relates to an electrode type steam vaporizer having an improved structure for preventing an electric shock at the time of feeding water, and an improved steam nozzle structure.
2. Description of the Prior Art:
In general, the electrode type steam vaporizer comprises a pair of electrodes in a container body as a water receptacle to heat water around the electrodes by passing current to the electrodes and vaporizing steam through a steam outlet of the container.
In the conventional electrode type steam vaporizers, electrodes made of graphite or stainless steel have been used. The surfaces of the electrodes have been corroded by a chemical reaction depositing an impurity thereon whereby it is necessary to disassemble and clean the surfaces of the electrodes after about ten days in normal use. Accordingly, in the conventional electrode type steam vaporizers, an electrode unit or an electrode heater unit has been assembled by securing the electrodes in a cylindrical housing having an opening and the unit is assembled in a container so as to be capable of assembly or disassembly by a simple hand operation such as a turning operation or a sliding operation. Water is fed into the container after disassembling the electrode unit through the aperture for connection of the electrode unit. However, when the electrode unit is easily disassembled and exposed by taking it out from the container, a child may disassemble the electrode unit as a play toy and break the electrode plates. If the electrode unit is disassembled from the container when connected to a power source, an accidental electric shock may happen.
When the electrode unit is disassembled from the container for feeding water into the container, water on the electrode surface may fall to cause a stain. The conventional electrode type steam vaporizer is convenient for disassembling the electrode unit for the cleaning of the electrode plates, however, there are various disadvantages as described above.
When the steam vaporizer is used only for few times or the corrosion of the surfaces of the electrodes is not substantial it is seldom necessary to clean the electrodes whereby the simplicity of assembly and disassembly of the electrode unit is not an important consideration.
When the electrodes are not corrosive, such as ferrite electrodes, it is enough to clean them once in six months under normal usage. In such a case, it is advantageous to have a structure wherein the electrode unit is fixed to the container body and the connection of the electrode unit and the water inlet are separately formed and water is fed through the water inlet. However, in such structure, it is dangerous to feed water while passing a current because the accident of electric shock may be caused. Accordingly, it is necessary to consider a safety structure.
The electrode type steam vaporizers are mainly used in home, whereby it is preferable to have a structure for preventing any accident caused by erroneous use. When an opening of a steam nozzle blocked, the steam pressure in the electrode type steam vaporizer may be abnormally increased whereby the steam vaporizer may be broken or hot water may be spread or high pressure steam may be abnormally discharged. It is necessary to consider the possibility of these accidents for safety reasons.
On the other hand, the emitted steam is cooled by the atmospheric condition at the steam outlet and is condensed as water drops and a water film may be formed by the surface tension of the water drops thereby closing the steam outlet. When the steam outlet is closed by the water film, the discharge of the steam is prevented whereby the steam may not be smoothly fed to a room. Accordingly, it is necessary to consider an improvement.
In the preparation of the container of the electrode type steam vaporizer, it is necessary to have an airtight structure except the connection of the electrode unit and the water inlet. Accordingly, it is preferable to prepare the container by blow-molding in one piece. However, it is difficult to prepare the container having a complicated structure in one piece by blow-molding. Accordingly, the container is prepared by molding an upper body and a lower body and bonding them with an adhesive composition. However, the bonding with an adhesive composition causes low adhesive strength and low airtightness. Accordingly, it has been considered to bond the upper body and the lower body by a rotary friction melt-bonding which is the method of immediately bonding with friction heat, two parts made of thermoplastic resin having a circular bonding surface under high speed rotation whereby high adhesive strength and high airtightness can be attained.
In conventional rotary friction melt-bonding, the bonding surfaces of the upper body 64 and the lower body 65 are contacted with each other without any space, and resin scraps 70 are deposited at the peripheral part of the bonding surfaces by the rotary friction melt-bonding (see FIG. 11) whereby the appearance is inferior and a scrap removing step is needed, thereby causing inferior processability.